Avalanche Forecast

Fair - Forecast snowfall amounts are uncertain

Sunday: 5-10 cm new snow expected, arriving late in the day. Freezing levels should stay at valley bottom. Winds moderate southwesterly. On Monday, unstable air will bring flurries, with no significant accumulation. On Tuesday, a Pacific frontal system will bring 15-20 cm new snow. Freezing levels are anticipated to go to around 1200 m. Strong westerly/southwesterly winds.

On Saturday, a widespread cycle of small avalanches (size 1) occurred in the most recent storm snow. Loose and slab avalanche activity was reported, with crowns up to 30 cm deep on all aspects and at all elevations. Explosive testing was able to produce slab avalanches to size 2.

15-20 cm new snow sits on the snow surface. This new snow came in much denser that the previous, cold storm snow (water to snow ratios of around 1:10, compared with 1:20 for the previous storm snow). Total 7-day storm amounts have been in the region of 60-100 cm and this has now settled into storm slabs around 30 -60cm thick. The primary layer of concern in the snowpack is the upper interface with the dense new snow and the low density old storm snow (down 20 cm or so). While not yet deep enough to result in large avalanches, this layer has been readily producing slab avalanches, which will increase in size as more storm snow arrives. The second layer of concern is a crust at the base of the old storm snow (down 50 cm or so) that exists below around 1900m. The bond with this crust appears to be quite good, however, on steep slopes this could easily act as a weak interface, potentially creating a layer for avalanches that initiate in the upper snow to step down to. Layers of concern deeper in the snowpack include a surface hoar/facet layer from mid-December and weak basal facets at the base of the snowpack in shallow snow areas. Both these have ceased to be of concern in the vast majority of locations. Snowpack depths in the region are around 240 cm.